So-called "demountable " interior partition wall systems have been available from Partition Components, Inc. (Markham, Ontario) and the Gold Bond Building Products Division of National Gypsum Company (the Gold Bond line is now available from Gravity Lock Systems, Inc., Houston, Tex.) since at least the issuance of U.S. Pat. Nos. 3,948,011 (in 1976) and 4,128,979 (in 1978), and their Canadian counterparts. Although these wall systems have been improved over the years to the point that their installation has been greatly simplified (indeed, although other tools are useful, the only tool needed for their installation is a rubber mallet), efforts are still underway to improve their cost advantages.
The above-mentioned U.S. Pat. No. 4,128,979 describes a so-called "suspension clip " which has proved to be the single most important component of a demountable wall system, and it is this component which, in spite of the ease of installation, occupies most of the installer's time as the partition wall is being erected. Consequently, significant time (and cost) savings could be realized if a clip was available which would simplify installation of a demountable wall system even further, and it is to this problem that the present invention is addressed.
One way to simplify installation of systems utilizing such suspension clips would be to improve the clips by making them unitary instead of making them from two pieces. Such slips are first disclosed in the afore-mentioned U.S. Pat. No. 3,948,011, and went through evolutionary changes as shown in U.S. Pat. Nos. 4,128,979 and 4,245,448, the latter issuing in 1981 and showing the clip in the embodiment which is being sold even to this date. However, all such clips require the assembly of two pieces; even more recent patents issued to entities and/or persons other than the originators of these clips and directed to other aspects of the walls erected using these clips such as U.S. Pat. Nos. 4,693,047 and 4,811,539, issued to National Gypsum Company in 1987 and 1989, respectively, show the clip as a two-piece assembly.
The only disclosure of a single piece suspension clip of which Applicant is aware appears in U.S. Pat. Nos. 5,060,434 (also shown in somewhat modified form in U.S. Pat. No. 5,216,859, a continuation-in-part of U.S. Pat. No. 5,060,434), licensed to Gravity Lock Systems, Inc., and a published PCT application, No. WO-83/02635. For a variety of reasons, the clip shown in U.S. Pat. No. 5,060,434 is of limited utility, but the clip shown in WO-83/02635 is so much closer in structure to the clip of the present invention that only the disadvantages and limitations of the latter are addressed here.
The most significant disadvantage of the clip shown in WO-83/02635 stems from the intention that the clip be used in a so-called "edge grip " system. In other words, as shown in FIGS. 1 and 2 of that published application, when the clip is affixed to a gypsum board, it is positioned near the edge of the gypsum board. Each clip is provided with a lateral extension 12 on the opposed long edges of a central plate 9, and as shown in FIG. 2, if the clip is affixed at the left edge of a gypsum board panel, the left-hand extension 12 is bent at approximately a 90.degree. angle away from the panel and is received in a slot (not separately numbered in the figures) in the face of the vertical studs which support the panel as shown in FIG. 4. This structure does not allow the gypsum board panel to be moved laterally into abutment with an adjacent panel, which is an important advantage of the system shown in the above-referenced U.S. Pat. Nos. 3,948,011, 4,128,979, and 4,245,448, which greatly facilitates the erection of the wall.
More important, however, is the cut 14 (best shown in FIGS. 5 and 8) formed in the clip shown in WO-83/02635. The clip shown in the three referenced U.S. patents effectively functions to draw a gypsum board panel tight against the studs because of the action of the weight of the panel on the angled portion of the clip which engages the horizontal support members mounted to the vertical studs, resulting in adjacent panels which are not only flush with each other but which are effectively retained in that flush relationship by the downward force on the panels The cut 14 in the clip shown in WO-83/02635, however, rests on the edge of the slot formed in the studs and the panel to which that clip is affixed is not affirmatively and tightly held against the studs. The edge of the lateral extension 12 of the clip shown in WO-83/02635 does include an angled portion (shown at reference numeral 17), but that angled portion appears to function only as an aid to the insertion of the lateral extension 12 into the slots in the studs. That clip is, therefore, limited in utility in the sense that to obtain a wall with the smooth, flat surface which is easily obtained with the clip used in the system shown in the three referenced U.S. patents requires that the installer spend extra time installing the wall, so as to minimize variation from one panel to another, and then taping and floating the joints between panels. It is, therefore, a principal object of the present invention to provide a unitary suspension clip for mounting a gypsum board panel to a vertical framework which retains the advantages of this "camming " action of the two-piece suspension clip shown in U.S. Pat. Nos. 4,128,979 and 4,245,448 which results in the drawing of adjacent panels into flush relationship and then firmly holds the panels flush with each other.
It is also an object of the present invention to provide a suspension clip which allows a partition wall of the type shown in U.S. Pat. Nos. 3,948,011, 4,128,979, and 4,245,448 to be assembled more quickly.
Another object of the present invention is to provide a suspension clip which can be affixed to a gypsum board panel at a location remote from the site of the wall into which the panel is being assembled.
Other objects, and the advantages, of the present invention will be made clear to those skilled in the art by the following description of a presently preferred embodiment thereof.